Recent advances in genetic engineering have provided the requisite tools to transform plants to contain foreign genes. It is now possible to produce plants which have unique characteristics of agronomic and crop processing importance. The ability to chose the tissues in which to express such foreign genes and the time during plant growth to obtain expression is possible through the choice of a regulatory sequence which turns on the gene, called the promoter. A wide range of promoters are known for various plants, plant tissues, and developmental stages.
The tomato is a very important plant for genetic engineering. It is readily transformed to express foreign genes and has many characteristics which are known to be improved by certain genes. It is also a valuable crop plant in many countries and was the first transgenic food crop approved for sale in the U.S.
Promoters useful in expressing foreign genes in tomato and other fruits are known. For example, the solids content of tomato fruit can be increased by expressing an ADPglucose pyrophosphorylase gene behind a fruit specific promoter. (Kishore, PCT Appl. WO 91/19806). The promoter from the 2A11 genomic clone (Pear, et al. (1989) Plant Mol. Biol. 13:639-651) will control expression of ADPglucose pyrophosphorylase in tomato fruit. The E4 and E8 promoters (Deikman, et al. (1988) The EMBO Journal 7:3315-3320), as well as the promoter for polygalacturonase are known to be fruit specific. However, the last three are limited to expression during a late stage in the development of the tomato fruit and so are known as red fruit promoters. The 2A11 promoter will cause expression during early stages, but is weaker than desired for some genes. Therefore, there is a need for stronger promoters which will cause expression of a gene during the development of the green fruit.
It is an object of the present invention to provide such promoters. It is a further object of the present invention to provide promoters which will function as fruit-specific in tomatoes and other fruit-bearing crops. It is a still further object of the present invention to provide DNA constructs containing these promoters and a gene encoding a desired protein or the antisense sequence for a less desirable protein.